IL-32 was abundantly expressed in the synovial tissues of rheumatoid arthritis patients. (a) In situ hybridization of the synovial tissues from rheumatoid arthritis (RA) patients. IL-32β was expressed in the synovial-infiltrated lymphocytes of RA patients. HE stain, hematoxylin and eosin stain. We examined the tissue samples from four RA patients, and show representative examples. (b) IL-32 expression of the synovial fibroblasts derived from four RA patients in response to human tumor necrosis factor alpha (hTNFα).